I will say I got BER when I had tomatoes in the EBs--and that should have been a perfect solution for watering. It did cut WAY down on the cracking from water uptake. I think what I've read is that when a young plant is growing rapidly, it can't transport the Ca ions fast enough to the developing fruit, and that's what does it. As the plant matures, the uptake rates even out a little better with the growth rates, and the problem corrects itself.
But, just as Jayne says, it's always sompthin!